Pump



Sept. 2, 1941.

H. MULLER ETAL PUMP Filed Aug. 12, 1939 3 Sheets-Sheet 1 F'g. I

Sept. 2, 1941. MULLER ET AL PUMP Filed Aug. 12, 1939 3 Sheets-Sheet 2 Inverfors Sept. 2, 1941. H.V MULLER AL PUMP Filed Aug. 12. 1939 3 Sheets-Sheet 3 !nventors W Patcnte Sept-e %4 1 e U ITED STA'I'ES. PATE oFsica Heinut Miler, Cologne-Bayenthal, and Anton Pischinger, Cologne-Dentz, Germany to Klckner Humboidt De'tz,

sclai't, Cologne-Dentz, Germany, a corporation Germany Application August 1 i Iu Germany S org Aktieng- 2, 1939, Serial No. 289342 ptenler 2,1933

o Claims. `c. 123-139) This invention relates to pumps o! the kind comprising a positively driven piston guided in a cylinder and having an axially extendingbore, which receives a. spring loaded equalizing piston and therewith forms a pumpchamber. This type o! pump is well suited for injecting fuel into the cyiinder of an internal combustion engine and may be constructed to give an intermittent injection. as described in our copending application Serial No. 1891768, filed February 10, 1938, issued July 9, 1940, as Patent No. &206.914;

In such a pump there is a ring-shaped space between the pump cylinder and the equalizing piston within which reciprocates the end of the positively driven piston. In accordance with the present invention this ring-shaped space is used. as a second pump chamber by providing controlledinlet and-outlet means therefor. 'For this purpose the equalizing piston mayhave an an- `nular collar coacting with a seat on the cylinder at the end of the ring-shaped chamber, to serve as a, delivery valve; or a spring capinterposed between the spring and the equalizing piston may i act as the delivery yvalve. 'The fluid may be sucked through a port controlled by the positively' -driven piston.

which the ring-shaped stroke space serves as a g The pumping of a. fluid, in accordance with this. V

invention, by means of the ring-shapedstroke space of the positively driven piston,'which is necessa-ily present in'this type of pump, has the advantage that an additional pump and its drive are dispensed 'with. The ring-shaped stroke space is particularly suited for this purpose, because the outer and inner pistons, for their service as pistons of the injection pump, are already accurately ground and can thereore pump a second fluid without any change or further work.. u

In a preterred form of the invention the ringshaped 'strokespace of the injection pump, sometimes hereinai'ter referred to as the "ring pump," is used as a feeder pump'for the fuel, that is, it

serves to pump the !uel from "the reservoir or a conduit to the inlet of the injectionptunp; The

leakage losses between the equalizing piston and the bore of the positively driven piston pass di'- rectly into the pump 'chamber of the feeder pump. Connections or channels !or leading-oli the leakage ruei are thereforenot required on the low pressure side of the injection pump. since the teeder pump must have a capacity at least equal to the greatest qua'tity pumped by the injection pump, which is to be regulated according to the load on the internal combustion engine, the excess mel must b permitted to run off. This `8 'may take place, for example, through a pressure limit valve, the spring strength of which cor responds to the desired supply pressure. The

excess Iuel may also be' conducted through a throttle, the flow resistance through which produces the necessary pressure in the suction chamber of the injection pump, which pressure may also be used !or the reguiation of the quantity of fuel to be Injected. Forjhis purpose the pressure is brought to work upon a spring loaded piston ora diaph'agm, which operates the reguieeder pump !or the iniection pump:

Fig. 2 is a vertical section' of 'jzf modified fo oi' pump;

Fig. 3 is a diagram of a modified uel pumping system wherein the ring pump serves as a Ieeder .pump and also as a regulating pump;

Fig. 4 is, a diagram of a further modified system, wherein the ringpump supplies a iquid for cooling the i'uei injection valve, in this case .thefuel itself; and

Fig. 5 'is a diagram o! 'still another modification wherein the ring pump acts as a lubrication pump. v

The pump shown in Fig. 1 has a piston 2 fltting in ai cylinder i and driven positively in the usual manner by a, cam c; also an equalizing piston l loaded by a spring &and Operating in a 1011811-- tudinal bor'e o! the piston 2. The pistons are shown in the lower .dead center position.'that is.

in the position before the beginning of the pump stroke. The fuel is drawn into the pump space III through a duct 5 in cylinder I, a transverse port E in piston 2, and ducts 'I in the equalizing piston 4. The manner ot operation oi' ,the injection pump is the same as described in our application. serial No; 189.768. After the piston 2 in the first part of its upward movement'ha interrup .the connection between the ducts 5 and 1, the equalizing piston' l iscarrie'd the pressure of spring 3. The ports and 8 oi the piston 2 alternately connect the pump space o with a return conduit- Il, lla and an injection conduit !2. na leading to a iuel injection valve 23. The piston 2 can be angularly rotated, by means not shown, to vary the position of ports 8 in relation to the inclined lower edge II of the equalizing piston 4, thus varying the portion .of the charge in chamber o which escapes through return conduit H and consequently the quantity oi' fuel .pumped through po'rts 9 and conduit |2 to the injection valve 23. The angular position of piston 4 is fixed by a screw 40. the nd of which engages in a slot 4l in the periphery of a. collar 42 onpiston 4.

The slot 4| and a hole 43 maintains open communi'cation between the ring'chamber |4 and the space |4a above the collar. Between the piston' 4 and spring 3 is interposed a spring cap i'l, which receives a pin 44 on the upper end of piston 4 in a socket 45. The bottom face of spring cap Il seats upon a shoulder 46 ot cylinder l atacent;

' vided with the same reference characters.

the ,upper end of the ring chamber l4, to perform the'function of a delivery valve.

The ring-shaped stroke space u, which in FigT 1 is used as a feeder pump, communicates, in the position ot the pistons shown, with a suction duct !6 connected with a supply conduit |6a leading from a tuel. reservoir |5. When the piston 2 moves upward, first the suction port s is covered and thereupon thespring cap ll is raised from its seat. The fuel compressed in the ring chamber l4 passesinto the chamber s housing the equalizing spring 3 and from there through a tube I !a into a filter IS. The filter is connected by a pipe lsa with the suction duct 5 of the injection pump. In the case of a multi-cylinder pump the individual pumps may be connected to a common filter s, the upper space'of whi'ch serves as an air chamber.

act simultaneously, an equalizatio'n must be provided for in this way.

The excess fue pumped by the ring pump, which 'is not taken up by the injection pump, Dasses through a pressure limit valve 20 and a conduit !I back into the fuel reservoir IS. A

filter 22 may be inserted in the supply conduit through a -hole 24 in the middle oi' the spring plate l'la, which, as in Fig. 1, has a peripheral ring surface 'ground to the seat 46. Between the spring cap I'Ia and the end 25 of the equalizing piston 4 which is remote rrom the pump space o, there is, in the position shown, a small space !or the entrance o! the fuel. As soon as 'the piston 2 moves upward !rom the lower dead center position shown, the equalizing piston 4 is immediately carried along with it and the suction port 24 in the spring cap is immediately closed. The quantity of fuel which has been taken into the pump space l4 is 'th'ereupon pumped through the delivery valve and the port 23 to a filter (not shown) corre- Since the injection pump and the ring pump of the same 'cylinder sponding to the filter Is, thence to the pump space of the ring pump. If the ring pump should fail for any reason, the drive of the machine will necessariy be interrupted,

simplified, as compared with Fig. 1. For instance, 4

there is no separate cap interposed between the spring 3 and piston 4, the collar 42 ot the piston acting both as spring cap and delivery valve. However, the operation and control can be exactly the same. Corresponding parts ar'e thereore pro- The unit is distinguished from' that of Fig, 1 by the fact that the part of the fuel pumped in the ring chamber |4 which is not conducted to the suction port 5 passes through a. pipe 41 to a cylinder 21, in which is a piston 30 connected with the reguiating rod 28 and influenced by a spring 29. The regulating rod 28 engages a spur gear 48 on piston 2 and imparts thereto the angular adjustment which controls the quantity of i'uel'injected,

as previously described. The back pressure built up in the regulating cylinder 21 behind a throttle 3 I, displaces the piston 2 according to the load and speed in such a way that a nearly uniform speed is maintained. The fuel leaving throttle 3| returns through a pipe 49 to the fuel reservoir !5.

In Fig. 4 the ring pump sucks fue] from the' can be used for pumping lubricating oil to the bearings 36 of the engine. The pump chamber of the injection pump and the ring pump are naturally entirely independent oi each other.

The ring pump can be used for additional auxiliary purposes, such as for a control pump for the starting air-valves. Furthermore, the embodiments shown in Figs. 1-4 can be combined in various ways. For example, the ring pump can pump exclusively a regulating fluid, or the, regulating fluid can serve 'at the same time as a cooling medium. i

We claim: I I

1. A pump comprising a cylinder; a piston fltting in said cylinder having an open ended axially extending bore; an inner piston fltting in said bore: said pistons iorming an inner pump chamber within said bore and, in conjunction with said cylinder, forming a second ring-shaped pump chamber; means tor positively reciprocating said first piston; means yieldingly pressing said inner ber within said bore and, in conjunction with said cylinder, formi'ng a second ring-shaped pump chamber; means tor positively -eciprocating said first piston; a spring pressing said inner piston into said bore; adelivery valve controlling said ring-shaped pump chamber. comprising a member movable with said inner piston against the action of said spring; inlet means for said ringshaped pump chamber; and' inlet and outlet means i'or said inner pump chamber.

3. A-pump comprising a cylinder; a piston fltting in said cylinder having an open ended axially extending bore; an inner piston fltting in said bore; said pistons forming an inner pump chamber within said bore and, in conjunction with said cylinder, forming a second ring-shaped pump chamber; means for positively reciprocating said first piston; a spring' pressing said inner piston into said bore; said cyinder having an annular chamber and said inner piston having an'annular shoulder coacting with saidseat to form a delivery valve for said ring-shaped pump chamber; inlet means for said ring-shaped pump chamber; and inlet and outlet means for said inner pumpchamber.

having a valve seat adiacent one 'end of said ring-shaped pump chamber against which said spring cap seats to form a delivery valve for said ring-shaped .pump chamber; inlet means for said 4 ring-shaped pump chamber; and inlet and outlet means for said inner pump chamber.

5. A pump compriing a cylinder: a piston fiti seat adjacent one e'nd of said ring-shaped pump V 4. A pump comprising a cylinde'; 'a piston fltfor positively reciprocating said first piston;

means yieidingly pressing said inner piston into said bore; inlet and outlet means for each of said pump chambers; a fuel reservoir; a conduit connecting said reservoir with the inlet means of said ring-shaped pump chamber; a fuel injection valve; a conduit connecting the outlet means of said inner pump chamber with said fuel injection valve; conduit means connecting the outlet means of said ring-shaped pump chamber with the inlet means of said inner pump chamber; means for regulating the amount of fuel pumped to said fuel injection valve from said inner pump chamber; means for diverting from said conduit means fuel pumped from said ring-shaped pump chamber in excess of that pumped from said inner pump chamber; a conduit for returning i said excess fuel to said reservoir; a throttle in said ting in said cylinder having an open ended axially extending bore; an inner piston fitting in said bore; said pistons forming an inner pump chamber within said bore and, in conjmction with said cylinder, forming a second ring-shaped pump chamber; means for positively reciprocating said first piston; a spring pressing said inner piston into said bore; said cylinder having an extension torming a chamber around said spring; `a spring cap interposed'between said spring and said inner piston; said cylinder having a valve seat adjacent one end' of said ring-sha'ped pump chamber against which said spring'cap seats to form a delivery valve for said ring-shaped pump chamber; means for conducting a liquid into saidspring chamber; said spring cap having an aperture to adnit liquid from said spring chamber into said ring-shaped chamber; said inner piston being spaced fromsaid spring cap in one end position and being adapted to close said aperture in said spring cap, upon moving into contact with said spring cap; and inlet and outlet means for said inner pump chamber.

6. A pump as described in claim 1, in combination with a liquid reservoir; a conduit connecting said reservoir with the inlet mea'nsof said ring-shaped pump chamber; and a conduit connecting the outlet means of 'said ring-shaped pump chamber with the inlet means of said inner pump chamber.

7. A pump as described in claim 1, in combination with a liquid reservoir; a conduit connecting said reservoir with the inlet means oi' said ring-shaped pump chamber; a conduit connecting the outiet means of said ring-shaped pump chamber with the inlet means of said inner pump chamber; and means for returning excess liquid from said last mentioned 'conduit to said reservoir.

8. In a pumping device for an internal combustion engine, a cylinder; a piston fitting in said cylinder having an open ended axially extending bore; an inner piston fitting in said bore; said pistons forming an inner pumpchamber within said bore and; in conjunction with said cylinder, forming a' second ring-shaped pump chamber; means last mentioned conduit; and pressure responsive means interposed in said last mentioned conduit behind said throttle controlling' said reguiating v means.

9. `In a pumping device for an internal combustion engine, a cylinder; a piston fitting in said g cylinder having an open ended axially extending bore; an inner piston fitting in said bore;

said pistons forming an inner pump chamber within said bore' and, in conjunction with said cylnder, forming a second ring-shaped pump chamber; means for positively reciprocating said first piston; means yieldingly pressing 'said inner piston into said bore; inlet and outlet means for each of said pump chambers; a fuel reservoir; a conduit connecting said reservoir with' the inlet means of said ring-shaped pump chamber; a fuel iniection valve; a conduit connecting the outlet means of said inner pump chamber with said fuel injection valve; conduit means connecting the outlet means of said ring-shaped pump chamber with the inlet means of said inner pump chamber; means for returning fuel from said conduit means to said reservoir; and a pressure limiting valve controlling the diversion-of fuel through said last means to said reservoir.

10. In a pumping device for an internal combustion engine, a cylinder; a piston fitting in said cylinder having an open ended axiaiiy extending bore; an inner piston fitting in said bore:

said pistons forming an inner pump chamber within said bore and, in conjunction with said cylnder, forming a second ring-shaped pump chamber; means for positively reciprocating said first piston; means -yieldingly 'pressing said inner piston into said bore; inlet and outlet means for each of said pump chambers; a fuel reservoir means for conveying fuel 'from said reservoir to the inlet means of said ring-shaped pump chamber; means for conveying fuel f-rom the outlet means o'f said ring-shaped pump chamber to the 

